1. Field of the Invention
The present invention relates to a battery connecting structure included in a power supply device used in a hybrid vehicle, an electric vehicle and the like.
2. Description of the Related Art
Conventionally, in an electric vehicle running by using an electric motor and a hybrid vehicle running by using both an engine and electric motor, the above power supply device is mounted as a drive source of the electric motor. For example, the power-supply device has a battery assembly and a pair of battery connecting structures (see patent document 1). The battery assembly is constructed by alternately inversely overlapping a plurality of batteries with each other. In one side of the battery, a positive electrode is provided, and in the other side thereof, a negative electrode is provided. The pair of battery connecting structures are attached to one side of the battery assembly and the other side thereof respectively. Further, FIG. 17 is a plan view showing a part of a conventional battery connecting structure.
The battery connecting structure 202 shown in FIG. 17 has a plurality of bus bars 203, a plurality of terminals 204, a plurality of electric wires 205 and a plate 206. The bus bar 203 connects a plurality of electric wires in series by connecting the positive electrode of the battery next to each other of the battery assembly and the negative electrode thereof. The terminals 204 are connected with each of the bus bar 203, and detect voltage of the battery. The electric wires 205 are connected with each of the terminal 204 respectively. The bus bar 203, the terminal 204 and the electric wire 205 are received in the plate 206 which is made of synthetic resin. Furthermore, the battery is provided with a cylindrical positive electrode projecting from one side of a box case, and a cylindrical negative electrode projecting from the other side thereof.
An arrow X in FIG. 17 shows an overlapping direction of the plurality of batteries and a longitudinal direction of the battery assembly. Also, an arrow Y in FIG. 17 shows a height direction of each the battery (namely, a height direction of the battery assembly). The battery assembly is mounted on a vehicle in a direction which the height direction (arrow Y direction) is in parallel to a gravitational direction. In other words, in a condition that the battery assembly is mounted on the vehicle, the above described positive electrode and negative electrodes project from a side of each battery in a horizontal direction.
The above bus bar 203 is formed into a plate shape by metal plate, and has a pair of bus bar holes 203a. In the pair of the bus bar holes 203a, the positive and negative electrodes of the battery arranged adjacent to each other are inserted. In the bus bar 203, the positive and negative electrodes of the adjacent battery are electrically connected by inserting the positive and negative electrodes of the battery adjacent to each other into the pair of the bus bar holes 203a. 
The above terminal 204 is made by pressing a metal plate. In the terminal 204, a bus bar connecting portion 241 connected with the bus bar 203 and a wire connecting portion 242 connected with the electric wire 205 are provided together. The bus bar connecting portion 241 is formed in a plate shape, and has a terminal hole 241a. In the terminal hole 241a, one of the positive electrode or the negative electrode is inserted. The bus bar connecting portion 241 is overlapped with the bus bar 203 and connected thereto in a condition that one of the positive electrode or the negative electrode is inserted into the terminal hole 241a. The wire connecting portion 242 has a pair of crimping pieces 243 which are electrically connected to a core wire of the electric wire 205 by pressing the core wire thereof. Further, the electric wire 205 is connected to a voltage detecting circuit (not shown).
The above plate 206 integrally includes a plurality of bus bar receiving portions 261, an electric wire receiving portion 262 and a plurality of wire connection receiving portions 263. The bus bar receiving portion 261 is formed in a box shape which the bus bar 203 can be inserted into, and receives each the bus bar 203 and the bus bar connecting portion 241 overlapped on the bus bar 203. In a bottom wall of the bus bar receiving portion 261, a pair of plate holes (not shown) which can insert the positive and negative electrodes of the battery respectively are provided. The electric wire receiving portion 262 is formed in a gutter shape, and receives the plurality of the electric wires 205 connected with the wire connecting portion 242. The wire connection receiving portion 263 is formed in a gutter shape communicating with each the bus bar receiving portion 261 and the electric wire receiving portion 262, and receives each the wire connecting portion 242 and an end of the electric wire 205 which is connected to the wire connecting portion 242. Moreover, the wire connection receiving portion 263 leads the electric wire 205 into the electric wire receiving portion 262.
In addition, the bus bar receiving portion 261 and the electric wire receiving portion 262 are arranged at intervals in parallel to each other. Each of the wire connection receiving portions 263 is arranged between each the bus bar receiving portion 261 and the electric wire receiving portion 262. In regard to such the above battery connecting structure 202, one of the positive electrode or the negative electrode which is inserted into the plate hole, the bus bar hole 203a and the terminal hole 241a, the wire connection receiving portion 263 and the electric wire receiving portion 262 are linearly arranged along a vertical direction (namely, the arrow Y direction).
The battery connecting structure 202 having the construction described above construction is assembled as below. First, the bus bar 203, the terminal 204, the plate 206 and others are separately produced. Further, the electric wire 205 is previously connected to the wire connecting portion 242 of the terminal 204. When the electric wire 205 and the wire connecting portion 242 are connected, first, the core wire is exposed by removing an insulating cover of the end portion of the electric wire 205. And, after the core wire is positioned between the pair of the crimping pieces 243, the pair of the crimping pieces 243 is crimped. Then, by crimping the pair of the crimping pieces 243, the core wire of the electric wire 205 is fixed in the wire connecting portion 242 by applying pressure. As a result, the wire connecting portion 242 and the electric wire 205 are connected.
Next, each the bus bar 203 is received in each the bus bar receiving portion 261 of the plate 206 so that the plate hole, not shown, and the bus bar hole 203a are overlapped. And then, each the bus bar connecting portion 241 is overlapped on each the bus bar 203 so that one of the pair of the bus bar holes 203a and the terminal hole 241a are overlapped, and is received in each the bus bar receiving portion 261. In this case, each the bus bar connecting portion 241 is overlapped on each the bus bar 203 so as to receive each the wire connecting portion 242 in each wire connection receiving portion 263. Thereafter, each the electric wire 205 is received in the electric wire receiving portion 262. The battery connecting structure 202 is assembled in this way.
Furthermore, the battery connecting structure 202 assembled by the above mentioned procedure is overlapped on a one side surface of the battery assembly or the other side surface. Then, a nut is screwed in the positive electrode and the negative electrode which are inserted into the plate hole, the bus bar hole 203a and the terminal hole 241a. Thereby, the battery connecting structure 202 is installed in the battery assembly.
[Patent Document] JP2006-269104
However, in the above mentioned battery connecting structure 202, there is a problem described below. More specifically, in the conventional battery connecting structure 202, the wire connecting portion 242 and the electric wire 205 which is connected with the wire connecting portion 242 are received in the wire connection receiving portion 263 smaller than the bus bar receiving portion 261 and the electric wire receiving portion 262 in width. Furthermore, density of the wire connection receiving portion 263 is high, in other words, a space in the wire connection receiving portion 263 is small. Thereby, water droplet which is occurred by condensation and so on flow from the electric wire receiving portion 262 into the wire connection receiving portion 263 through a surface of the electric wire 205 by capillary action. As a result, there is a problem such that the drop of water is easy to adhere to the wire connecting portion 242 and the core wire of the electric wire 205 which is connected with the wire connecting portion 242. Additionally, in the wire connection receiving portion 263, as previously mentioned, the density thereof become high. Thereby, it is difficult to discharge the water droplet collected in an inside thereof. For this reason, further, there is a problem such that the wire connecting portion 242 and the core wire of the electric wire 205 are at risk of being exposed to water for a long time.
Furthermore, in the conventional battery connecting structure 202, the positive electrode or the negative electrode which is inserted into the plate hole, the bus bar hole 203a and the terminal hole 241, the wire connection receiving portion 263 and the electric wire receiving portion 262 are arranged along the vertical direction(namely, the arrow Y direction). Thereby, the water droplet occurred by condensation and so on adheres to the positive electrode or the negative electrode, and the falling water droplet flows into the electric wire receiving portion 262 through the wire connection receiving portion 263. Therefore, there is a problem such that the water droplet is more likely to attach to the wire connecting portion 242 received in the wire connection receiving portion 263 and the core wire of the electric wire 205 connected with the wire connecting portion 242. In addition, it is undesirable that the water droplet adheres to the battery connecting structure because it causes rust and so on.
Besides, in the conventional battery connecting structure 202, the wire connecting portion 242 of the terminal 204 has the pair of the crimping pieces 243 which attaches the core wire of the electric wire 205 by pressure. Thereby, after connecting the wire connecting portion 242 and the electric wire 205, it is necessary to receive the terminal 204 and the electric wire 205 in the plate 206. As a result, the work receiving the terminal 204 and the electric wire 205 in the plate 206 may be a difficult work. For this reason, the work receiving the terminal 204 and the electric wire 205 in the plate 206 needs to perform by hand work. Therefore, costs may quite high.
Furthermore, in the conventional battery connecting structure 202, in order to reduce load of the wire connecting portion 242 occurred by rotating the terminal 204 around the terminal hole 241a when the nut is screwed on the positive electrode or the negative electrode which is inserted into the terminal hole 241a of the terminal 204, a projection 241b for stopping its rotation is provided in the terminal 204, and a projection receiving portion 261a which the projection 241b is inserted is provided in a side wall of the bus bar receiving portion 261. Thereby, even if the terminal 204 is rotated when screwing the nut, the rotation is controlled because the projection 241b abuts against an inner surface of the projection receiving portion 261a. As just described, in the conventional battery connecting structure 202, it is necessary to have the projection 241b for rotation stop and the projection receiving portion 261a. Therefore, size of the terminal 204 and the plate 206 is increased.